KR100444718B1 - Cathode Ray Tube - Google Patents

Abstract

A pair of supports 13a and 13b disposed in parallel to each other and a shadow mask 11 serving as a color selection electrode in which a plurality of openings are arranged, the shadow mask being tensioned in a state where tension is applied by the support; In the provided and supported cathode ray tube, in the state before the shadow mask is tensioned, the shape of the opening such that the opening width of the middle portion in the tensioning direction of the opening gradually decreases from the center portion to both ends in a direction parallel to the longitudinal direction of the support. To change. Thereby, the shape of the opening can be made uniform over the entire surface in the state where the shadow mask is tensioned. As a result, a cathode ray tube with less color spots can be provided.

Description

Cathode Ray Tube {Cathode Ray Tube}

The present invention relates to a cathode ray tube, and more particularly, to a cathode ray tube having a shadow mask in which tension is applied in one direction to which tension is applied.

In the color cathode ray tube, the electron beam emitted from the electron gun irradiates the phosphor screen formed on the inner surface of the face panel, and a desired image is displayed. On the electron gun side of the phosphor screen, a shadow mask serving as a color selection electrode is formed at a predetermined distance. In the shadow mask, a plurality of substantially rectangular openings (electron beam through holes) are arranged so that the electron beams collide by emitting a phosphor at a predetermined position.

When the electron beam impinges on the shadow mask, the shadow mask thermally expands. As a result, the opening position changes, and the electron beam passing through the opening exits the phosphor at the predetermined position correctly and does not collide, resulting in color staining. This phenomenon is called doming. In order to prevent this, the shadow mask is tensioned and maintained in the frame in a state where tension is previously given to the shadow mask so as to absorb thermal expansion due to temperature rise. By maintaining such tension provision, even if the temperature of the shadow mask rises, the relative positional shift between the opening of the shadow mask and the phosphor stripe formed on the phosphor screen can be reduced.

The phosphor screen is obtained by arranging an approximately rectangular frame-shaped black stripe with the vertical direction in the longitudinal direction, and then forming phosphors corresponding to each color of red green blue in the black stripe openings in order. The black stripe is formed through the exposure process through the shadow mask in a state in which the shadow mask is applied to the face panel with the tension applied as described above.

With the development of computer technology and the like, high-definition image display is required, and display pixels are increasingly fine pitched. In other words, the opening width of the shadow mask and the arrangement pitch of the black stripes are more accurate. This causes a problem that color spots of the display image occur on the entire screen.

As a result of examining the cause of this color spot, the inventors found that this is because the opening shape of the black stripe is unevenly formed in the whole screen.

10A and 10B are partially enlarged views schematically showing black stripes formed on the inner surface of the face panel. The up and down direction of the ground in both figures corresponds to the up and down direction of the screen of the cathode ray tube. 10A shows the pattern of formation of an ideal black stripe. As shown in Fig. 10A, when the black stripe is formed in a line shape consisting of a plurality of uniform parallel lines, color spots do not occur. By the way, in the cathode ray tube in which the above-mentioned color spots occurred, as shown in Fig. 10B, the lines were periodically dark in color, and black stripes were formed in a checkered pattern.

As a result of further examination, it was found that the above-mentioned checkered black stripe is because the opening of the shadow mask used for forming the black stripe is deformed into a shape different from the design shape.

11A and 11B are partially enlarged views of the shadow mask openings in which tension is applied to the mask frame. Arrows T in Figs. 11A and 11B indicate the tension applied to the shadow mask.

As shown, in the conventional shadow mask, the width (opening width in the direction orthogonal to the direction in which the tension T is applied) of the opening formed in the rectangular shape in the state before the tension is applied to the mask frame is applied to the mask frame. By applying the tension T to the shadow mask, the shadow mask is thinned at approximately the middle portion in the direction in which the tension T is applied, and is deformed into a so-called "failure shape" (FIG. 11A), or conversely in the approximately middle in the tension T direction. It became thick at the part and deformed into what is called a "cylindrical shape" (FIG. 11B). When the opening is deformed into a failure shape or a cylindrical shape in this manner, a checkered black stripe shown in Fig. 10B is formed.

In addition, in which state the opening of the shadow mask is deformed, depending on the size of the cathode ray tube (i.e., the size of the shadow mask), the amount of tension applied, and the like, the position of the shadow mask on the screen (i.e., the center of the screen) Or periphery).

As such, the opening shape of the shadow mask, which should be a uniform rectangle throughout the entire screen, is variously modified as described above by applying tension to the mask frame of the shadow mask. If the opening shape of the shadow mask differs depending on the position on the screen, the black stripe is also formed in a line shape as shown in Fig. 10A in some parts of the screen, and in a checkered pattern as shown in Fig. 10B in other parts. Therefore, the shape of each phosphor of red green blue formed in the opening of the black stripe is different in the screen, for example, there arises a problem that color staining occurs between the center and the peripheral portion of the screen.

An object of the present invention is to solve the above-mentioned conventional problem and to provide a cathode ray tube with less color spots by making all openings of the entire screen into a desired almost uniform shape in a state where tension is applied to a shadow mask.

1 is a cross-sectional view along the tube axis of the color cathode ray tube of the present invention;

Fig. 2 is a schematic perspective view of a mask structure installed in the color cathode ray tube of Fig. 1;

Fig. 3 is a front view showing a state before tensioning of the shadow mask of Embodiment 1 of the present invention used for a cathode ray tube having a diagonal size of 29 inches;

4 is a diagram showing a distribution in the X-axis direction of tension applied to the shadow mask of Embodiment 1 of the present invention;

5A and 5B are enlarged views showing the opening shape of the central portion in the X-axis direction and the end portion in the X-axis direction in the state before the shadow mask of the first embodiment of the present invention is tensioned;

Fig. 6 is an enlarged front view showing the formation state of the opening aimed at the shadow mask in the energized state;

Fig. 7 is a front view showing a state before tensioning of the shadow mask of Embodiment 2 of the present invention used for a cathode ray tube having a diagonal size of 25 inches;

Fig. 8 is a diagram showing the distribution in the X-axis direction of tension applied to the shadow mask of Embodiment 2 of the present invention;

9A and 9B are enlarged views showing the shapes of the openings in the center portion in the X-axis direction and the end portions in the X-axis direction, before the shadow mask of Embodiment 2 of the present invention is tensioned;

Fig. 10A is an enlarged view showing an ideal line-shaped black stripe formation pattern, and Fig. 10B is an enlarged view showing a checkered black stripe formation pattern;

11A and 11B are enlarged front views showing the deformation state of the opening of the shadow mask in the conventional cathode ray tube, and Fig. 11A shows the opening deformed into a bobbin shape, and Fig. 11B shows the opening deformed into a cylindrical shape, respectively. do.

<Description of the symbols for the main parts of the drawings>

1: color cathode ray tube 2: face panel

2a: phosphor screen 3: funnel

3a: neck part 4: electron gun

5: deflection yoke 6: electron beam

7: fixed pin 10: mask structure

11: shadow mask 12: opening

13a, 13b: support 14a, 14b: support member

15, 17: spring attachment member 16, 18: spring member

The present invention has the following configurations in order to achieve the above object.

The cathode ray tube of the present invention includes a pair of supports arranged in parallel to each other and a shadow mask functioning as a color selection electrode in which a plurality of openings are arranged, wherein the shadow mask is in the state where tension is applied by the support. A cathode ray tube in which tension is maintained on a support, wherein an opening width of an intermediate portion in the tensioning direction of the opening is parallel to a longitudinal direction of the support in a state before the shadow mask is tensioned on the support. The shape of the opening is changed so as to gradually decrease toward.

According to this structure, since the shadow mask which changed the opening shape in the direction orthogonal to the direction to which tension is applied before the shadow mask is tensioned is used, the opening of a uniform shape is spread over the whole surface in the tension applied state. You can get it. As a result, a cathode ray tube with less color spots can be provided.

It is preferable that the width of the shadow mask in the direction parallel to the longitudinal direction of the support of the shadow mask in the state before the shadow mask is applied to the support is wide at both ends of the tension applying direction and narrow at the middle. Further, in the direction parallel to the longitudinal direction of the support, the tension applied to the shadow mask at the center portion is preferably greater than the tension applied to the shadow mask at both ends.

In the substantially rectangular shape, for example, the opening formed in the center portion in the direction parallel to the longitudinal direction of the support in the state before the shadow mask is applied to the support has a thick cylindrical portion in the middle of the tensioning direction. The openings formed at both ends in a direction parallel to the longitudinal direction of the support may have a narrow failure shape in the middle of the tensioning direction.

<Embodiment of the invention>

1 is a cross-sectional view of the color cathode ray tube of the present invention. The colored cathode ray tube 1 shown in Fig. 1 has a face panel 2 having a rectangular phosphor screen 2a formed on its inner surface, a funnel 3 connected to the rear of the face panel 2, and a funnel 3; The electron gun 4 built in the neck portion 3a of the slit portion 2 and the shadow mask 11 are provided inside the face panel 2 so as to face the phosphor screen 2a. In addition, a deflection yoke 5 is provided on the outer circumferential surface of the funnel 3 in order to deflect the electron beam 6 emitted from the electron gun 4 and to scan the phosphor screen 2a.

The shadow mask 11 plays a role of color discrimination for the three electron beams 6 emitted from the electron gun 4, and a plurality of roughly slotted holes, which are electron beam through holes, are formed on the metal plate by etching. Formed.

For convenience of description below, an XYZ-3D Cartesian coordinate system is set in which the horizontal axis passing through the tube axis and orthogonal to the tube axis is the X axis, the vertical axis passing through the tube axis and the orthogonal axis perpendicular to the tube axis is the Y axis and the tube axis is the Z axis. do.

FIG. 2 is a schematic perspective view of a mask structure 10 comprising a shadow mask 11 installed in the color cathode ray tube 1 of FIG. 1 and a mask frame provided with tension applied thereto.

The mask structure 10 has a pair of supports 13a, 13b having a substantially L-shaped cross section, a pair of support members 14a, 14b having a hollow rectangular columnar shape, and a pair of supports 13a, 13b in the Y-axis direction. The shadow mask 11 is tensioned in a state in which a tension T is applied. A pair of supports 13a and 13b spaced apart by a predetermined distance and arranged in parallel in the X-axis direction, and a pair of support members 14a and 14b deformed into a substantially "co" shape in a substantially rectangular frame form. Then, it welds in each junction part and comprises a mask frame.

The shadow mask 11 has a shape that can be regarded as a rectangular shape, and its long side end portion is welded to the free end side end portions of the supports 13a and 13b. At this time, while applying an external force in a direction approaching the free end side ends of the pair of supports 13a and 13b to each other, the end portion in the Y-axis direction of the shadow mask 11 is gripped and a tension is applied in the Y-axis direction. By welding and fixing the shadow mask 11 to the pair of supports 13a and 13b, the shadow mask 11 is tensioned in a state in which a tension T in the Y-axis direction parallel to the short side is applied, as shown. Is given. In the shadow mask 11, openings 12 which are a plurality of electron beam through holes are formed by etching (only a part of openings 12 are schematically shown in FIG. 2).

As shown in Fig. 1, a plate-shaped spring attaching member 15 is fixed to the outer circumferential surfaces of the pair of supports 13a and 13b, and a spring-shaped spring member 16 is fixed to the spring attaching member 15, have. Similarly, the plate-shaped spring attachment member 17 is fixed to the pair of support members 14a and 14b, and the plate spring shape 18 is fixed to the spring attachment member 17.

The fixing pins 7 are embedded in the four inner wall surfaces of the face panel 2. The mask structure 10 is provided in the face panel 2 by inserting these four fixing pins 7 into the holes formed in the spring members 16 and 18.

The opening 12 formed in the shadow mask 11 of the present invention is formed in a predetermined shape before applying the tension so that the mask structure 10 is tensioned and supported to have a desired uniform rectangular shape in a supported state. have.

This will be described below.

(Embodiment 1)

Fig. 3 is a front view showing the shadow mask of Embodiment 1 used in a cathode ray tube having a diagonal size of 29 inches in a state before tensioning. In the shadow mask of this embodiment, both ends in the X-axis direction are recessed in an arc shape (that is, the width in the X-axis direction of the shadow mask is wide at both ends in the Y-axis direction and narrow at the middle part), and has a so-called failure shape. The dashed-dotted line 21a, 21b shows the holding part of the tension provision machine which gives a predetermined tension to a shadow mask when a shadow mask is force-proofed to a mask frame. Portions in the gripping portions 21a and 21b are cut out after tension is applied to the mask frame. In Fig. 3, the length Lh = 541mm in the X-axis direction at the end of the Y-axis direction, the pair of supports of the mask frame for tensioning the shadow mask (the spacing Wv = 410mm between the supports 13a and 13b in Fig. 2, the length in the Y-axis direction). Lv = 550 mm and the radius of curvature R of the arcs at both ends in the X axis direction R = 5000 mm The center of the arc is formed on the X axis.

FIG. 4 is a view showing an outline of the distribution in the X-axis direction of the tension applied to the shadow mask when the shadow mask shown in FIG. 3 is tensioned to the mask frame as shown in FIG. In Fig. 4, the horizontal axis indicates the position in the X-axis direction, and the center of the screen (intersection between the X-axis and the tube-axis) is represented by X = 0 (mm), and the positive direction of the X-axis is displayed toward the screen to the right. In addition, the vertical axis represents the tension at each point on the X axis. As shown, the tension applied to the shadow mask is not uniform in the X-axis direction, and the screen center portion is larger than both ends.

The shadow mask of this embodiment corresponds to such a tension distribution in the X-axis direction, and changes the opening shape in the X-axis direction as follows in the state before tension application.

The details of the shape of the openings in the center portion 5A and the end portion 5B in the X-axis direction in Fig. 3 in the state before tensioning the mask frame are shown in Figs. 5A and 5B, respectively. As shown, in this embodiment, the opening of the area | region 5A of the center part of an X-axis direction is formed in the cylindrical shape which made the width | variety (opening width of an X-axis direction) thick at the middle part of a Y-axis direction, and both ends of an X-axis direction The opening of the area | region 5B of this is formed in the bobbin shape which narrowed the width | variety (opening width of an X-axis direction) in the middle part of a Y-axis direction, and forms the shape of the opening from the center part 5A to the edge part 5B. It is formed by gradually changing from a cylindrical shape to a bobbin shape.

The specific dimensions of the openings are indicated.

Fig. 6 is an enlarged front view showing the formation state of the target opening in the state where the shadow mask is tensioned. In the shadow mask for the 29-inch cathode ray tube of the present embodiment, the opening has a substantially precise rectangular shape, and the opening width W = 0.2 mm in the X axis direction, the opening width H = 10 mm in the Y axis direction, and the arrangement pitch Ph in the X axis direction. = 0.8 mm and array pitch Pv = 11 mm in the Y-axis direction.

In the state before tension application, when the maximum opening width in the X axis direction of the cylindrical opening shown in Fig. 5A and the minimum opening width in the X axis direction of the bobbin-shaped opening shown in Fig. 5B are both WO, The correction rate C (%) of the opening width in the direction is defined as C = (WO-W) / W × 100. At this time, each correction rate C of the cylindrical opening (center part 5A of FIG. 3) of FIG. 5A, and the bobbin-shaped opening (end 5B of FIG. 3) of FIG. 5B is +3% and -5, respectively. %to be. And the correction rate of the opening between the center part 5A and the edge part 5B is gradually changing from +3% to -5%. In addition, the opening width of the end portion in the Y-axis direction is almost constant (the end portion 5B is 1% narrower with respect to the center portion 5A).

Tension is applied while applying the tension shown in Fig. 4 to the shadow mask having the openings as described above, and the mask structure 10 shown in Fig. 2 is constituted to form a uniform rectangular opening as designed over the entire surface. Confirmed that. In addition, when the cathode ray tube 1 shown in Fig. 1 having the mask structure 10 incorporated therein, almost no color spot was found over the entire screen.

(Embodiment 2)

Fig. 7 is a front view showing a state before tension application of the shadow mask of the second embodiment used for a cathode ray tube having a diagonal size of 25 inches. The shadow mask of the present embodiment has a so-called bobbin shape in which both ends of the X-axis direction are recessed in an arc shape (that is, the width of the shadow mask in the X-axis direction is wide at both ends in the Y-axis direction and narrow at the middle part). . The dashed-dotted line 21a, 21b shows the holding part of the tension provision machine which gives a predetermined tension to a shadow mask when applying a shadow mask to a mask frame. Portions in the gripping portions 21a and 21b are cut out after tensioning the mask frame. In Fig. 7, the length Lh = 487mm in the X-axis direction at the end of the Y-axis direction, and the shadow mask is a pair of supports of the mask frame given tension (the spacing Wv = 360mm of the supports 13a, 13b in Fig. 2, Y-axis direction The length Lv = 550 mm and the radius of curvature R of the arcs at both ends in the X axis direction R = 2500 mm The center of the arc is formed on the X axis.

FIG. 8 is a diagram showing an outline of the distribution in the X-axis direction of the tension applied to the shadow mask when the shadow mask shown in FIG. 7 is applied to the mask frame as shown in FIG. . As shown, the tension applied to the shadow mask is not uniform in the X-axis direction, and the screen center portion is larger than both ends.

The shadow mask of this embodiment corresponds to such tension distribution in the X-axis direction, and changes the opening shape in the state before tension application in the X-axis direction as follows.

In the state before tensioning the mask frame, details of the opening shape of the center portion 9A and the end portion 9B in the X-axis direction in Fig. 7 are shown in Figs. 9A and 9B, respectively. As shown, in the present embodiment, the openings in either the region 9A in the center portion in the X-axis direction and the region 9B in the both end portions are tapered in the width in the middle portion of the Y-axis direction (opening width in the X-axis direction). It is formed in a shape.

The specific dimensions of the openings are indicated.

In Fig. 6 showing the arrangement of the rectangular openings targeted for the shadow mask under tension, the opening width W = 0.2 mm in the X-axis direction of the opening, the opening width H = 10.5 mm in the Y-axis direction, and the X-axis direction. The array pitch Ph is 0.8 mm and the array pitch Pv in the Y-axis direction is 11 mm.

When all the minimum opening widths in the X-axis direction of the bobbin-shape openings shown in Figs. 9A and 9B were all WO before the tension was applied, the correction rate C (%) of the opening width in the X-axis direction was set to C = (W0-. It is defined as W) / W × 100. At this time, each correction rate C of the bobbin-shaped opening (center part 9A of FIG. 7) of FIG. 9A and the bobbin-shaped opening (end 9B of FIG. 7) of -5%,- 7%. Then, the correction rate of the opening between the ends 9B in the central portion 9A is gradually changed from -5% to -7%. In addition, the opening width of the end portion in the Y-axis direction is almost constant (the end portion 9B is 1% narrower with respect to the center portion 9A).

By applying the tension shown in Fig. 8 to the shadow mask having the above-mentioned openings and applying the tension, the mask structure 10 shown in Fig. 2 is constituted so as to have a uniform rectangular opening as designed over the entire surface. Confirmed. In addition, when the cathode ray tube 1 shown in Fig. 1 having the mask structure 10 incorporated therein, almost no color spot was found over the entire screen.

The specific example of Embodiment 1, 2 shown above is an example for demonstrating this invention, and this invention is not limited to this numerical example. According to the examination of the present inventors, in the shadow mask in which the tension having the distribution shown in Figs. 4 and 8 is applied in the Y-axis direction, the opening width in the middle portion of the Y-axis direction in the state before the tension is applied is both ends from the center portion in the X-axis direction. It is preferable to form the opening so that it gradually decreases toward (ie, the correction rate C is gradually decreased toward the both ends from the center portion in the X-axis direction). At this time, the opening width of both ends of the opening in the Y-axis direction is substantially constant in the X-axis direction. Accordingly, in a specific embodiment, in addition to the first and second embodiments described above, the openings in the center and both ends of the X-axis direction are both cylindrical, and the maximum opening width is formed so as to gradually decrease from the center to both ends in the X-axis direction. You may also. What is necessary is just to consider the size of each part of a shadow mask, the magnitude | size and distribution of the tension applied, etc. to make it a form.

As shown in Figs. 3 and 7, a shadow mask having an external shape having a bobbin shape in which the width of the middle portion in the tensioning direction is narrowed is used in a direction perpendicular to the same tensioning direction as in Figs. It becomes the maximum in the center part and becomes the tension distribution gradually decreasing toward both ends.

In the above example, the case where the tension is applied in the short side direction of the shadow mask has been described, but the present invention can also be applied when the tension is applied in the long side direction. In this case, what is necessary is just to change an opening shape gradually as mentioned above between the center part and both ends of a short side direction. In this case, it goes without saying that the scanning line direction becomes the short side direction, and the long axis direction of the opening of the shadow mask becomes the long side direction.

As described above, according to the present invention, since the shadow mask in which the opening shape is changed in a direction orthogonal to the direction in which tension is applied in the state before applying the shadow mask is used, the shape is uniform over the entire surface in the state where tension is applied. The opening of can be obtained. As a result, a cathode ray tube with less color spots can be provided.

Claims (4)

A pair of supports arranged in parallel to each other and a shadow mask functioning as a color selection electrode in which a plurality of openings are arranged, the shadow mask being tensioned by the support in a state where tension is applied by the support; As a supported cathode ray tube, In the state before the shadow mask is tensioned to the support, the shape of the opening is changed so that the opening width of the middle portion of the tensioning direction of the opening gradually decreases from the center portion to both ends in a direction parallel to the longitudinal direction of the support. Cathode ray tube characterized in that laid. The width of the shadow mask in a direction parallel to the longitudinal direction of the support of the shadow mask in the state before the shadow mask is tensioned is wide at both ends of the tensioning direction and narrow at the middle. Cathode ray tube. The cathode ray tube according to claim 1, wherein in the direction parallel to the longitudinal direction of the support, the tension applied to the shadow mask at the central portion is greater than the tension applied to the shadow mask at both ends. The said opening formed in the center part of the direction parallel to the longitudinal direction of the said support body is a thick cylindrical shape of the intermediate part of the said tension application direction, The shadow mask is made to the support body before tensioning. And the openings formed at both ends in a direction parallel to the longitudinal direction have a thin failure shape in the middle of the tension applying direction.